Different energy conversion systems exist for converting mechanical energy to fluid energy, i.e. fluid pressure. One such system is a fluid compression system, such as a pump, whereby a force is applied on an enclosed fluid, thereby raising the pressure of the fluid. An example of this type of pump is a common bicycle pump, such as used to inflate tires. Another example is a piston and cylinder system, whereby mechanical work is done by the piston on the fluid inside the cylinder, thereby compressing or raising the pressure of this fluid. This system is commonly used in internal combustion engines.
However, many difficulties arise in these types of fluid compression systems. For instance, it has always been challenging to rapidly raise the fluid pressure in systems having pistons actuated at relatively low frequencies (e.g. less than about 5 Hz) with relatively small constant forces (e.g. 25 lb). One of the difficulties that exist with the piston and cylinder system is that the cylinder is often quite long and requires the piston to travel a relatively long distance in order to achieve high compression ratios. The length of the cylinder therefore requires that the system be of a certain size which may not be practical in all applicable situations. Furthermore, because of the length of the cylinder, the piston may require a sizable amount of time before the piston reaches the end of its cycle. In the case of pumps, such as a bicycle tire pump, the pump often requires a user to exert minimal force for a short period of time, until the pressure builds in the tire, in which case the pump requires a substantial amount of force from a user to further pressurize the tire. Bicycle pumps may also require a large stroke length, as in piston and cylinder systems.
Therefore, there yet exists room for improvement in terms of efficiently converting mechanical energy to fluid energy, i.e. fluid pressure, such as in fluid compression systems.